1. Field of the Invention
The present invention relates to a train control system, and particularly to a ground device that transmits train control information to an on-board device mounted on a train to control the speed and the like of the train.
2. Description of Related Art
Train control systems are configured such that an on-board device mounted on a train controls the speed and the like of the train based on a train control signal received from a ground device to ensure the safe traveling of the train. As such train control systems, various systems have been conventionally proposed (refer to Japanese Laid-Open Patent Application Publication No. 2010-36803, Japanese Laid-Open Patent Application Publication No. 2008-162548).
Conventionally, one train control system has been applied to one train line (zone), and trains on which on-board devices for train control systems of respectively different types are mounted have not been able to travel on a route within the same train line (zone). This is because the structure for detecting the position of a train, the kind of train position information, and the like are different depending on the type of train control system, and train position information and the like cannot be shared between train control systems of different types. This is also because an on-board device can receive a train control signal only from a ground device for a train control system of the same type and hence safe traveling within a train line (zone) cannot be ensured.
With the development of railroad networks, the need to permit trains on which on-board devices for train control systems of respectively different types are mounted to enter part of a train line or a specific zone may arise. However, it is difficult for the conventional techniques to meet such a need.
Furthermore, when an existing system is changed to a new system, there is a need to achieve a balance between commercial operations by the existing system and the adjustment of the new system during the transition. Therefore, upon changing the system, after a ground device for the new system is installed, an on-board device for the new system must be added to trains with an on-board device for the existing system mounted thereon, and after the completion of the adjustment of the new system, the on-board device for the existing system must be removed. In other words, the vehicles need to be altered at least twice, and this requires much time and effort at system change.